Effect of Scanning Speed on Microstructure, Mechanical, and Tribological Properties of Sic/Ti Composites Via Laser Powder Bed Fusion

Abstract

Laser powder bed fusion (LPBF) of particle-reinforced metal matrix composites (MMCs) enables precise fabrication of complex geometries while achieving superior strength, wear resistance, and thermal stability. This study investigates the influence of laser scanning speed on the microstructure and mechanical properties of silicon carbide (SiC)-reinforced pure titanium (Ti) composites processed via LPBF. A 1 wt.% SiC/Ti composite was fabricated to evaluate the role of SiC particles in the LPBF process. The findings reveal that increasing scanning speed significantly enhances heterogeneous nucleation within Ti grains due to the presence of SiC particles, thereby increasing nucleation sites and promoting grain refinement. The mechanical properties initially improve with higher scanning speeds, but decline beyond an optimal threshold. The optimal performance was achieved at a laser power of 140 W and scanning speed of 1000 mm/s, yielding a high relative density, a yield strength of 1097 MPa, and an ultimate tensile strength of 939 MPa. Compared to pure Ti, the hardness and tensile strength of the composite increased by approximately 70%. Additionally, SiC particles reacted to form TiC and other novel phases, further augmenting hardness and strength. These results provide critical insights into the relationship between laser scanning speed, microstructural evolution, and mechanical performance, offering valuable guidance for optimizing SiC/Ti composites in structural and tribological applications.

Keywords: Laser powder bed fusion (LPBF), Titanium matrix composites, Scan speed, Microstructure, Mechanical properties